Carbon-holder for arc-lamps.



J. C. LA CHANCE.

CARBON HOLDER FOR ARC LAMPS.

APPLICATION FILED JULY I. 1916.

1,278; 171. Patented Sept. 10, 1918..

Fig.1.

WI THE 885 8:

I a IIWENTOR .f, Cilia (fiance A TTOR/VEYS JOSEPH C. LA. CHANCE, OF VANCOUVER, BRITISH COLUMBIA, CANADA.

CARBON-HOLDER FOR ARC-LAMPS.

-Specification of Letters Patent.

Patented Sept. 10, 1918.

Application filed July 7, 1916. Serial No. 108,035.

To all whom it may concern Be it known that I, JOSEPH C. LA CHANCE, a citizen of the Dominion of Canada, residing at Vancouver, in the Province of British Columbia, Canada, have invented certain new and useful Improvements in Carbon- Holders for Arc-Lamps, of which the following is a specification.

This invention relates to a carbon holder for an arc lamp of that class used to exhibit moving pictures, the object of the invention bein to provide a more rapid and satisfacto means for clamping or releasing the car on, with a more efiectite contact making hold of the same.

In existin carbon holders where the carbon is held n its adjustment by screw ressure directly applied to the clam mem ers, the heat to WhlCh the clamp mem ers are exposed causes oxidation and a slight arcing at the contact. This slight arcing rapidly burns away the carbon and it becomes loose at the clamping contact when arcing at the contact becomes excessive, to the injury of the clamp members and the waste of current.

The existing carbon holders are also inconvenient to adjust or renew and much time is lost'in affording them the required attention.

These objections are overcome in the carbon holder, which is the subject of this applicatlon, by clamping the carbon with a sprin pressure which is sufficient to insure an e ective, contact with the carbon, and whichwill follow up any slight reduction of carbon at the place of contact, whereby the carbon cannot become loose and are to any considerable extent. The spring pressure being applied through a leverage, the spring is removed from the immediate proximity of the heat from the arc and may be further protected, if considered desirable, by a shield.

Pressure of this spring is relieved to remove or ad ust the carbon by an eccentric acting between the free ends of the clamping levers, by which means the carbon may be released or secured by one simple movement.

The invention is particularly described in the followin specification, reference being made-to the rawings by which it is accom' paniedin which:

Figure 1 is a side elevation of the carbon holder, showing the carbon in position, and

2 is a plan oi thesame. I

In these drawings 2 represents the end of one of the carbon holding arms of the arc lamp, which end may be integral with the arm or removably attached to it as found convenient. The end of 2 is T-shaped as at 3 to form the fixed half of the clamp and is vertically groov'edto receive the carbon 4. It has a portion 5 forwardly projecting from one end which is shouldered to receive the jawed end of the movable clamp member 6, attachment being made by a pin 7. The member 6 is also grooved to receive the car; bon 4 that such may be held between the two grooves.

The free end of the clamp member 6 is connected to the corresponding end of 3 by a rod 8 which passes through apertures in the ends of 3 and 6 and is headed at 9 at one end and at the other end is threaded to re ceive a milled nut 10, between which nut and the back face of 3 is a coiled spring 11, a washer 12 bein interposed between the milled nut and t e spring, which washer may fit within the coil and prevent dlsplacement of it.

The clamp member 6 is thus held tightly against the carbon 4 in the grooves of 3 and 6 by the spring 11 multiplied by the leverage of the clamp member.

The clamping pressure being resilient will accommodate itself to expansion and contraction due to changes of temperature, or to any slight reduction of the carbon due to arcing. The carbon may be released by moving apart the free ends of the clamp which may be effected in any convenient manner by the rotation of the end of a screw driver or the like inserted between them, or, as shown in the drawing, by an eccentric 13 mounted on a screw 14 in the end of 3 opposite the free end of the clamp member 6, which eccentric may have a cross rib 15 by which it may be rotated by means of a pliers or wrench, the edge of the eccen-. tric 13 hearing on a projection 16 from the end of 6.

The apertures in the end of the clamp members 3. and 6 are enlarged or elongated slightly to ermit angular movement of the rod 8 in them when the clamp is opened and a washer 17 angled and notched into the face of 6 to permit of such movement,

drilled in it to take the pin 7, so that the clamps may be used with different sizes of carbons.

So constructed, as previously stated, a constant resilient pressure is imposed on the carbon which insures effective contact therewith under all conditions, and the carbon may be rapidly released for adjustment and renewal by simply pressing the free end of the clamp members apart and may be again secured by release of such separating means.

Having now particularly described my invention, I hereby declare that What I claim as new and desire to be protected in by Letters Patent, is:

A carbon holder for an arc lamp, comprising an arm having a cross piece at one end, said cross piece being curved to receive the carbon and having an aperture, an ear projecting from one end of said cross piece, an apertured clamping lever pivoted to said ear, the other end of said cross piece being apertured, a tension rod passing through the apertures of said cross piece and said clamping lever and having a head provided with a knife edge bearing against said lever, a coil spring on said tension rod for drawing said lever toward said cross piece to clamp the carbon, and a cam member on said cross piece with its plane extending parallel to said spring for engaging said lever to move it against the tension of the spring and thereby release the carbon.

In testimony whereof I affix my signature.

JOSEPH 0. LA CHANCE. 

